부산대학교 도서관

Background: To date, no specific therapy or vaccination is available for West Nile virus (WNV) infections in humans; preventive strategies represent the only possibility to control transmission. To focus these strategies, detailed knowledge of the virus dynamics is of paramount importance. However, several aspects of WNV transmission are still unclear, especially regarding the role of potential vertebrate host species. Whereas mosquitoes' intrinsic characteristics cause them to favour certain hosts (host preference), absolute selection is impossible in natural settings. Conversely, the selection carried out among available hosts and influenced from hosts' availability and other ecological/environmental factors is defined as host selection. Methodology/Principal findings: In July 2022, we searched PubMed database for original articles exploring host selection among WNV-transmitting Culex mosquitoes, the main WNV vector. We considered only original field studies estimating and reporting forage ratio. This index results from the ratio between the proportion of blood meals taken by mosquitoes on potential host species and the hosts' relative abundance. From the originally retrieved 585 articles, 9 matched the inclusion criteria and were included in this review. All but one of the included studies were conducted in the Americas, six in the United States, and one each in Mexico and Colombia. The remaining study was conducted in Italy. American Robin, Northern Cardinal, and House Finch were the most significantly preferred birds in the Americas, Common Blackbird in Italy. Conclusions/Significance: Although ornithophilic, all observed WNV-transmitting mosquitoes presented opportunistic feeding behaviour. All the observed species showed potential to act as bridges for zoonotic diseases, feeding also on humans. All the observed mosquitoes presented host selection patterns and did not feed on hosts as expected by chance alone. The articles observe different species of mosquitoes in different environments. In addition, the way the relative host abundance was determined differed. Finally, this review is not systematic. Therefore, the translation of our results to different settings should be conducted cautiously. Author summary: West Nile virus (WNV) is a mosquito-borne virus that can cause a neuroinvasive and potentially deadly disease in vertebrates (including humans). The disease is transmitted from vectors (mostly Culex mosquitoes) during the blood meal. As no specific therapy or vaccination are available, the control of human cases centres on mosquitoes–humans contact prevention. For these reasons, deep knowledge of WNV transmission dynamics is considered paramount to focus preventive strategies. Nevertheless, WNV transmission dynamics are still unclear, especially regarding the role of potential hosts. Mosquitoes are intrinsically attracted from one host over another. However, in natural settings, absolute selection is often impossible. Therefore, in this review, we aimed at summarising knowledge on WNV-transmitting mosquitoes' host selection in natural settings. We specifically considered original scientific publications calculating forage ratio for Culex mosquitoes. The forage ratio is the proportion of the relative abundance of blood meals taken from a potential host in trapped mosquitoes and that host's relative abundance. Our results suggest that all observed Culex mosquitoes presented an opportunistic feeding behaviour and the potential to transmit zoonotic pathogens, since they all fed also on humans. Moreover, all the observed mosquitoes fed on hosts with a certain degree of selection, rather than what might be expected by host abundance alone. [ABSTRACT FROM AUTHOR]